It's been said that a role-playing game lives or dies by it's combat system. Every system out there has a more-or-less detailed system to deal with combat, with varying levels of success for the character, and varying levels of damage for the target. However, when it comes to dealing with confrontations that are other than what most games consider combat, like a good argument or trying to convince someone to do something against their best interests, it comes down to a little talk and a single die roll. And let's face it, there are more opportunities for role-playing during a good argument than there are in a swordfight. Dogs in the Vineyard uses the same conflict resolution system for all types of conflict, including the verbal kind. So verbal exchanges receive the same attention to detail that gunfighting does. Playing out a verbal exchange in steps, where you can start to lose ground and then try to find a way to gain it back, or start out well only to have your opponent yank the carpet out from under you at the last, adds an element to role-playing that hasn't been there before.

Although short demo conflicts tend to sound like a Monty Python sketch. "Let's have an argument..."

Actually, no Brother Seth. What you're talking is referred to as a "Sacred Cow" around the Forge, ie. a commonly accepted idea that isn't necessarily true.

Specifically, Combat Systems are in no way necessary to a good roleplaying game. Further, and more generically true, Systems separate from the "main" resolution mechanic dedicated to combat resolution are in no way necessary. Dogs falls under the latter case;

Now, that doesn't necessarily mean that games with dedicated combat mechanics are bad; The point of this idea is if you're designing a game in which combat is not a main focus, or not even supposed to happen at all, then including combat specific mechanics is a bad idea.

I personally prefer combat in my games, so I'm not extremely familiar with a lot of games without a combat mechanic, but there's notably more than one, especially among those that come out of designers who are regulars here on the Forge. A lot of these games have a central mechanic which can cover combat, but don't differentiate between combat and other forms of conflict.

Dogs' treatment of conflicts as all the same, whether they're "combat" or not, has lots of precedence. The particular games I learned it from were, let's see, Universalis, Sorcerer, the Pool, My Life with Master, Trollbabe, InSpectres, Dust Devils ... and probably several more I'm missing. These are games that I'd read, or played, or followed the development of, before and while I designed Dogs.

(Also I don't think I'm allowed to talk about this without mentioning Hero Quest, but I haven't played or read it. It's the game that all those other games' designers learned it from.)